Urban Heat Island Effects and Thermal Comfort in Abuja Municipal Area Council of Nigeria

Abstract

Climate change is a global challenge with multiple consequences. One of its impacts is the increase in surface temperature intensity. The hazard is higher for populaces living in urban areas, where the most elevated temperatures are commonly recognized, because of the Urban Heat Island (UHI) effect. The city of Abuja in recent times has experienced an increase in both surface and atmospheric temperatures. In this study, an evaluation of the ecological impact of UHI effect of Abuja Municipal area was conducted using Landsat 8 data of 2019. The surface temperature of the city was estimated and evaluated using its thermal-infrared (TIR) band (10.40μm – 12.50μm). Furthermore, the correlation between LST and Normalized Difference Vegetation Index (NDVI) as well as the Normalized Difference Build-Up Index (NDBI) was also assessed to validate the accuracy of the LST. The urban thermal field variance index (UTFVI) was applied to measure the thermal comfort level of the city, which quantitatively assessed the UHI impacts on the nature of urban life. Results show that the LST of Abuja city ranges from approximately 19^oC to 39^oC with the UHI observed in the northern and eastern parts of the city. The UTFVI map associated with UHI indicates that the outer peripheries of the city are ecologically more comfortable than the inner segments. In general, 40% of the city experiences ecologically bad or worse UHI effects, indicating a need for continued UHI mitigation efforts.

Keywords: Urban Heat Island (UHI), Land surface temperature (LST), Urban Thermal Field Variance Index (UTFVI), Normalized Difference Vegetation  index (NDVI), Landsat OLI/TIRS